This invention relates to multi-contact interconnectors for connecting electric terminal points and, in particular, to novel and improved interconnectors that are flexible and valuable for use in the electric circuits of various kinds of precision electronic devices.
Along with the increasing trend in solid state electronic circuits toward miniaturization more and more, demand is rapidly growing for smaller and smaller interconnectors having the smallest distances between contact points. Miniature interconnectors with shock-proofness and reliability against vibration have been eagerly desired especially for display circuits in various kinds of precision portable devices, such as, dashboards of automobiles, pocketsize electronic calculators, electronic watches and the like.
Proposed as materials suitable for forming the contact points of the interconnectors of the above kind are various electrically conductive rubbery elastomers including silicone rubber rendered electro-conductive by adding a highly conductive filler, such as, carbon black or metal powder. These electrically conductive rubbery materials are capable of imparting to interconnectors good reproducibility and reliability against shocks and vibrations as well as wide versatility in shapes, dimensions, electric conductivity and distances between contact points.
An example of interconnectors manufactured using above electrically conductive rubbers materials as a the material for contact points is the so-called "striped" interconnector wherein of each conductive filler-containing silicone rubber layer and each nonconductive silicone rubber layer are stratified and lie one upon another. The stripe-type interconnectors are very valuable for use in liquid crystal displays and for contacting to substrates of printed circuits. However, it has been found that they are not always satisfactory with respect to contact uniformity and reliability, since their surfaces are smooth or flat, despite the resilience of the materials. These conventional multi-layer interconnectors possess the disadvantage of the possibilities of occasional failures in making reproducible electric contacts and consequently, abnormal operations of the circuits and devices.